G7 Qualification : The Art of Maintaining Color

G7 is a process, a color calibration method, that allows printers to gain repeatability across the gamut of printing devices and substrates. It requires financial and time commitments—both manpower and equipment.

There is a lot of confusion in the market about ISO 12647 and G7. Are they competing standards? Are they regional standards? Are they standards at all? Let me explain the relationship and some history for context.

ISO 12647 is a series of international printing standards, which describe “Process Control for Production of Halftone Color Separations, Proofs and Production Print.” There are currently seven standards covering parameters and measurements, offset, coldset, publication gravure, screen printing, flexo and proofing from digital data. There is an eighth standard going through the development process that covers print process from digital data.

These standards describe in great detail the proper methods and materials to be used, and the ways to monitor and measure the various printing processes. The one thing they don’t implicitly do is specify a resultant color characterization set. This is due to the variability inherent in the process itself—different papers, machine characteristics, etc.

As the globalization of business communication increases, so does the need to do work in a distributed way through the use of multiple printing processes across many countries, while achieving the same visual results. This increases the need for standard color characterization (color target definition) sets. Since there is already a set of printing standards, one would think that there should be an easy way to develop an agreed upon set of color characterizations by process and substrate.

However, since there is also a lot of technology available, there are actually many ways to not only develop color characterizations, but also many ways to achieve the same color characteristics. Currently there are a number of regionally developed color characterization sets available. These include GRACoL and SWOP, developed in the United States; a series of PSO sets developed in Germany; and many others around the globe.

The original ISO 12647 standards specify “tone value curves” as a way to control print. However since the original standards were developed, two more ways have been introduced to control print—color profiles and near neutral scales. To accommodate these additional methods, there was an ISO Technical Standard developed, ISO-TS 10128. It describes “methods of adjustment of the color reproduction printing system to match a set of characterization data.”

As a result of preference, the GRACoL and SWOP sets were created using “near neutral curves” (G7), while the PSO sets were created using tone value curves. Ultimately, the end result is an almost identical appearance when the comparable GRACoL and PSO sets are judged.

The G7 process, which was developed by IdeAlliance, is a method for producing near neutral curve sets. In essence, it is used as a calibration method that can be used in a print production process. While it is not an ISO standard in itself, G7 is method that conforms to ISO-TS 10128.

So the short answer is that there are many ways to get you to the same color place depending on your process preferences, and in the end, whichever option you choose relative to ISO-TS 10128 should allow you to achieve successful print production if you follow the process laid out in ISO 12647.—Dave Zwang, principal consultant of Zwang & Co., a firm specializing in process analysis, and strategic development of firms in the fields of electronic publishing, design, prepress, and printing.

Just mention the term G7 certification and you can hear a collective cringe coming from the folks at IDEAlliance, the printing industry association unofficially tasked with governing printing methodologies, specifications and standards. G7 is a “qualification” program; the law sees a difference between the terms. IDEAlliance is working on a certification program.

If you’re feeling a bit lost right now, take heart. G7 certi-, um, qualification is a subject that is relatively limited to the hard-core color cognoscenti. Relative to the industry, there are still very few G7 Master Printers (more than 500 at press time, with roughly 15 new ones each week). You can find them either by visiting the IDEAlliance Website, or you might happen to recognize them by their use of a logo.

OK, by now you’re hopping mad, and resent the exclusionary implications because you feel you understand color and proof matching just as much as the next shop.

You don’t need IDEAlliance or anyone else to validate what you’ve been doing for years, or decades. Your press work matches the proofs consistently. Frankly, you suspect this qualification smacks of a cash grab concocted by folks who think a little too highly of themselves and their calibration methods.

Buyers Dig Certificates

Fact of the matter is, there are a lot of people in the industry who can’t pick up the minor, subtle differences between proof and press. And those people are your existing or potential clients. But buyers, by nature, are drawn to certifications, qualifications and embossed stamps that declare someone or something as having been validated by an expert. That gives them the peace of mind to do business with a company that’s touting a quality logo.

“I can think of a number of times in recent months where (G7 qualification) has been a factor, particularly in the business development environment,” notes Bill Tucker, executive vice president of sales for Cincinnati-based Berman Printing.

Having achieved G7 status last year was one of the best investments we have made in some time. While the logo is nice to have, the real bang for the buck has been the far superior color match we are achieving on press. As our clients say, the proof is in the pudding, not the badge. It is when clients come on press checks that they become true believers in the certification.